Focusing on the use of advanced computational technologies within the design process the paper discusses the generation of a digital matrix to evaluate virtual, three-dimensional scenarios - including variations of geometry, light ambiances and material use - as a design decision tool. The emphasis of the research was placed on the digital representation of material appearance as one of the most a relevant parameter for the atmospheric quality of spaces. The case study Design Decision Matrix delivers a concept for a decision tool that on the one hand generates and displays design variations and offers on the other hand a clearly arranged visual interface for the decision process.@en